1. Field of the Invention
The present invention relates to a conveying apparatus conveying a recording medium and a recording apparatus recording an image on the recording medium.
2. Description of the Related Art
In recent years, recording apparatuses such as printers have commonly been applied not only to recording of texts on plain paper but also to recording of photographic images on dedicated photo paper. In particular, for ink jet printers, the size of ink droplets has been increasingly reduced, resulting in image quality equal to or higher than that of silver halide photos. Thus, high-precision conveying techniques for conveying recording media are demanded, and high-precision rollers including, for example, a metal shaft coated with a grinding stone are used as conveying rollers. Furthermore, the rotation amount of a DC motor is accurately and quickly controlled by a code wheel and an encoder sensor provided on a shaft of the conveying roller. This allows both high-precision and quick conveyance to be achieved.
Furthermore, to manage a recording position with respect to a recording medium, a paper end detecting unit for detecting the leading and trailing end positions of a conveyed sheet material is provided; the paper end detecting unit is made up of an optical sensor and a lever that shields a light receiving and emitting path of the sensor. When the sheet material comes into contact with the lever, the lever moves pivotally around a rotating shaft of the lever. A part of the lever then opens or shields an optical path for an optical sensor, which thus detects the end of the sheet material. The paper end detecting unit is configured to be able to detect the ends (leading and trailing ends) of sheet materials of all width sizes fed from an upstream side of the conveying roller.
With improved image quality provided by the recent recording apparatuses, there has been an increasing demand to enable recording on various recording media. By way of example, there has been a demand to enable recording on disk-shaped recording media (hereinafter referred to as “disk media”) such as CDs (Compact Discs) or DVDs (Digital Versatile Discs) the surface of which can be subjected to ink jet recording. The disk media have an inherent data recording surface located opposite to an ink jet recorded surface. The data recording surface is easily externally damaged. Thus, the disk medium cannot be independently set in the recording apparatus because of possible damage. Consequently, the disk medium essentially needs to be conveyed on a carrier using a dedicated tray. Furthermore, special recording media having the same shape as that of the carrier have recently been developed. For recording, such recording media can be stacked on a guide on which dedicated tray are stacked.
The rigidities of the disk media and the dedicated trays are higher than that of sheet materials such as paper. Thus, feeding the disk media from an auto sheet feeder (hereinafter referred to as an “ASF”) is difficult; the auto sheet feeder feeds sheet materials at any angle while bending the sheet materials, instead of feeding the sheet materials horizontally relative to the conveying roller. Thus, the recording apparatus for disk media includes a dedicated supply port. In general, the supply port dedicated to the disk media is often provided on the front side of the recording apparatus in order to simplify user operation. Furthermore, to allow a reduction in the size of the recording apparatus, the guide along which the tray dedicated to disk media is guided to the supply port generally has two positions, a supply position and a housing position instead of being always located in the supply position.
In such a recording apparatus, a PE sensor lever (Paper End detecting sensor lever) is configured as follows in order to reduce detection errors caused by a sheet material caught on the lever or flapping of the lever. That is, the tip of the lever is shaped and located so as to form an acute angle to an abutting portion of the sheet material in a sheet material conveying direction. The angle of the PE sensor lever is generally set with a sheet material feeding direction from ASF taken into account. When the PE sensor lever is located in a disk medium conveying path, if the tray is inserted through the disk media-only supply port, formed in the front of the recording apparatus as mentioned above, the tray may interfere with the PE sensor lever. Thus, the PE sensor lever may be damaged.
Thus, in the conventional art, as illustrated in FIGS. 8 and 9, a PE sensor lever (Paper End detecting sensor lever) 321 is positioned away from the conveying path for the disk media tray to prevent the tray from interfering with the PE sensor lever 321.
In FIGS. 8 and 9, a first sheet material A is a recording medium with the minimum width size that can be conveyed from the ASF (not illustrated in the drawings) of the recording apparatus. A second sheet material B is a recording medium with the maximum width size that can be conveyed from the ASF of the recording apparatus. A feeding roller 28 feeds sheet materials stacked on the ASF to a recording portion of the recording apparatus. Roller rubber 281 is installed on a part of the feeding roller 28. APE sensor 32 is attached to a chassis (not illustrated in the drawings). The PE sensor lever 321 shields and opens a light receiving portion and a light emitting portion of the sensor, which can then detect an end of the sheet. A conveying roller 36 forms a nip together with a pinch roller 37 biased from upward, to convey the recording medium. A discharging roller 40 is provided, in a recording medium conveying direction, on the downstream side of a carriage 5 with a recording head mounted thereon. The discharging roller 40 forms the nip together with an opposing spur (not illustrated in the drawings) to convey the recording medium, the trailing end of which has passed through the nip formed by the conveying roller 36 and the pinch roller 37, to discharge the recording medium to the exterior of the recording apparatus. A tray guide 1001 feeds a tray 1003 dedicated to disk media from the front of the recording apparatus to the interior of the main body. A tray 1003 is shaped to engage with a disk medium 1002, and includes a reflector 1004 located on the top surface thereof to detect the position of the tray 1003. As illustrated in FIGS. 8 and 9, a detecting portion (lever portion) of the PE sensor lever 321 and an end of the tray 1003 are arranged so as to set any distance dL between the detecting portion and the end, with the dimensional tolerances of the components and the possibility that the tray 1003 is slightly tilted during conveyance, taken into account.
As another conventional example, a construction has been proposed in which a PE sensor lever is retracted from a recording medium conveying path using a motor or solenoid that is dedicated to the retraction or also used for another driving purpose. FIG. 10 is a perspective view showing the construction of the conventional example. As illustrated in FIG. 10, a pinch roller 37 is located opposite a conveying roller (not illustrated in the drawings) to sandwichingly hold and convey a sheet. A pinch roller holder 30 holds the pinch roller. A PE sensor lever is illustrated at reference numeral 321. A lifting cam 1011 retracts the pinch roller holder and the PE sensor lever from the conveying path by a predetermined amount. A lifting gear 1012 is combined coaxially with the cam 1011. An intermediate roller and a cassette conveying motor are illustrated at reference numerals 86 and 85, respectively. Moreover, a plurality of driving gears arrays and planet gear arrays are illustrated at reference numerals 851 and 852, respectively. The intermediate roller 86 conveys, to a recording portion, the recording medium fed from a cassette (not illustrated in the drawings) located on the bottom surface of the recording apparatus.
FIGS. 11A to 11C are schematic sectional views illustrating a retracting operation in the conventional construction illustrated in FIG. 10.
FIG. 11A illustrates a normal recording operation standby state. In the state illustrated in FIG. 11A, the cassette feeding motor 85 is rotated. Then, driving is transmitted to the lifting gear 1012 via the planet gear arrays 852. The cassette conveying motor 85 is normally driven to feed the recording medium from the cassette. The rotating direction of the cassette conveying motor 85 is selected in response to a disk medium conveyance command, or the cassette conveying motor 85 is driven in the direction of a retracting operation by a unit such as a clutch. The conveyance instruction is given when for example, the tray guide 1001 is detected to be set in a disk insertion position or in response to an instruction from a printer driver.
When the lifting gear 1012 rotates, the lifting cam 1011, which is coaxial with the lifting gear 1012, is rotated to pivotally move the pinch roller holder 30 and the PE sensor lever 321. Thus, as illustrated in FIG. 11B, the PE sensor lever 321 is retracted from the conveying path for the tray 1003. Here, an operation is performed which sets the tray 1003 on the tray guide 1001 to insert the tray 1003 into the recording apparatus or draw the tray 1003 into the recording apparatus via the discharging roller 40. In this case, the PE sensor lever 321 has been retracted from the conveying path for the tray 1003 as illustrated in FIG. 11C. Thus, the tray 1003 can be fed into the recording apparatus main body while preventing the tray 1003 from interfering with the PE sensor lever 321. Such a conventional configuration is disclosed in Japanese Patent Application Laid-Open No. 2007-70105.
As another conventional example, a construction has been proposed in which a PE sensor lever is retracted from a recording medium conveying path in conjunction with adjustment of the distance (gap) between a recording medium and a recording head. A carriage with the recording head mounted thereon is supported on a guide shaft so as to be able to scan the recording medium in a direction orthogonal to a recording medium conveying direction. The proposed construction is configured so as to be able to retract the PE sensor lever from the recording medium conveying path in conjunction with operation of a lever that is a gap adjusting unit for operating the guide shaft upward and downward. Such a configuration is disclosed in Japanese Patent Application Laid-Open No. 2003-94740.
However, in the construction in which the PE sensor lever is located outside the recording medium conveying path as in the conventional example illustrated in FIG. 8 or 9, the width size of the recording apparatus is disadvantageously larger than the conventional one depending on the location of the PE sensor lever.
As illustrated in FIG. 12A, the size of the recording apparatus is determined by the width of the sheet material B with the corresponding maximum width size, the acceleration and deceleration distance S101 of a recording head 7, which performs recording on the sheet material B, and the arrangement of nozzles in the recording head 7. A recording operation is normally performed in a constant speed area S102 in which the recording head 7 carries out scanning at a constant speed. Thus, the total distance (S101+S102+S101) corresponds to the minimum distance required to move the recording head 7.
If the disk medium 1002 is conveyed within the area of the maximum width of the sheet material B such as a cut sheet as illustrated in FIG. 12A, the size of the recording apparatus is determined by the sheet material B with the maximum width size. However, if the disk medium 1002 is conveyed beyond the area corresponding to the maximum width of the sheet material B as illustrated in FIG. 12B, the constant speed area of the recording head 7 is S103. Thus, the constant speed area of the recording head 7 increases by dx=(S103−S102), thereby increasing the size of the recording apparatus by dx. Thus, in the construction in which the PE sensor lever is located outside the recording medium conveying path, the size of the recording apparatus may disadvantageously increase depending on the conveying path for the disk medium 1002.
Furthermore, in the construction in which the PE sensor lever 321 is located in the recording medium conveying path as illustrated in FIG. 13, an arrangement may be adopted which retracts the PE sensor lever 321 from the recording medium conveying path as in the case of Japanese Patent Application Laid-Open No. 2007-70105. However, in this case, apparatus costs may disadvantageously increase. This is because a dedicated motor needs to be provided to drive the PE sensor lever 321. Additionally, if an existing motor is also used to drive the PE sensor lever 321, a complicated sequence is required, thus making appropriate operation of the PE sensor lever 321 difficult. For example, if a retracting operation is started using opening or closing of a tray guide as a trigger, the PE sensor lever 321 disadvantageously cannot be quickly retracted from the recording medium conveying path. Moreover, in the construction in which the PE sensor lever 321 is retracted by driving the motor, the PE sensor lever 321 cannot be retracted while a power supply is off. Thus, when the tray 1003 is inserted into the apparatus in this state, the PE sensor lever 321 may disadvantageously be damaged.
Furthermore, in the construction in which the PE sensor lever is retracted in conjunction with the gap adjusting unit as in the case of Japanese Patent Application Laid-Open No. 2003-94740, the gap adjustment and the retraction of the PE sensor lever are simultaneously performed. This disadvantageously complicates the construction. Additionally, a detecting unit is disadvantageously required which detects whether or not a user has adjusted the gap.